The long term objective of this project is to improve the care of patients harboring intracranial, saccular aneurysms, which represent a major source of neurologic morbidity and mortality resulting from spontaneous aneurysm rupture or re-rupture. In the early 1990s the care of these patients was revolutionized by the development of detachable, platinum microcoils. These microcoils are placed into aneurysm cavities using minimally invasive, image guided, catheter based techniques, avoiding the need for open surgery in many or most patients. Notwithstanding the remarkable advantage offered by microcoils over traditional surgical approaches, important shortcomings still remain with coil technology. The primary drawback of coiling remains the frustratingly high rate of subacute and chronic aneurysm recanalization, seen in up to 50% in large aneurysms. Such recanalization not only exposes patients to risk of rebleeding but also to the risk of additional procedures, including both endovascular and open surgical approaches, in hopes of achieving permanent aneurysm closure. The exact biological mechanisms underlying the observed failure of platinum microcoils remain unclear. However, recent preclinical and clinical data from an entirely new class of embolic agents, termed "flow diverters," suggests that stabilizing the aneurysm neck, rather than filling the dome as coils do, is the ideal approach for permanently curing aneurysms. Current "flow diverters" are constructed of braided tubular structures, similar in character to endovascular stents but with markedly higher metallic coverage across the neck as compared to standard stents. These flow diverters have shown in animal models and in clinical case series remarkably high rates of complete and persistent aneurysm occlusion, even in large aneurysms. Unfortunately, these tubular, intraluminal flow diverters can be applied only in a minority of cases for two reasons. First, since they are intraluminal rather than intrasaccular devices they are associated with high risk for thromboembolic events, necessitating administration of dual antiplatelet therapy, which is undesirable in cases of acutely ruptured aneurysms. Second, the intraluminal flow diverters do not at present achieve immediate aneurysm occlusion, which further limits their use in ruptured aneurysms. Finally, the construction of these tubular flow diverters limits their use to side-wall aneurysms, which are less common that bifurcation aneurysm morphologies. The research and development program described in this Phase 1 SBIR proposal will facilitate introduction of an entirely new approach to aneurysm treatment: the use of "endosaccular" flow dividers. This device, termed the Woven EndoBridge (WEB) will achieve efficient flow diversion and, with high probability, excellent rates of acute and chronic aneurysm occlusion. The WEB will be applicable in a wide range of aneurysms morphologies and will be appropriate for treatment of both ruptured and unruptured aneurysms. If successful, this SBIR research program will substantially alter and improve care of patients suffering from intracranial aneurysms. PUBLIC HEALTH RELEVANCE: This research program is aimed at development of a new class of minimally invasive treatment for brain aneurysms, which are an important cause of stroke. The new device developed in this program will improve the safety and effectiveness of aneurysm treatment, without need for open brain surgery.